x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 87 insertions, 0 deletions

diff --git a/include/crypto/sm3.h b/include/crypto/sm3.h
new file mode 100644
index 000000000..371e8a661
--- /dev/null
+++ b/include/crypto/sm3.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * SM3 hash algorithm
+ *
+ * Copyright (C) 2017 ARM Limited or its affiliates.
+ * Copyright (C) 2017 Gilad Ben-Yossef <gilad@benyossef.com>
+ * Copyright (C) 2021 Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
+ */
+
+#ifndef _CRYPTO_SM3_H
+#define _CRYPTO_SM3_H
+
+#include <linux/types.h>
+
+#define SM3_DIGEST_SIZE	32
+#define SM3_BLOCK_SIZE	64
+
+#define SM3_IVA		0x7380166f
+#define SM3_IVB		0x4914b2b9
+#define SM3_IVC		0x172442d7
+#define SM3_IVD		0xda8a0600
+#define SM3_IVE		0xa96f30bc
+#define SM3_IVF		0x163138aa
+#define SM3_IVG		0xe38dee4d
+#define SM3_IVH		0xb0fb0e4e
+
+/* State for the SM3 compression function */
+struct sm3_block_state {
+	u32 h[SM3_DIGEST_SIZE / 4];
+};
+
+/**
+ * struct sm3_ctx - Context for hashing a message with SM3
+ * @state: the compression function state
+ * @bytecount: number of bytes processed so far
+ * @buf: partial block buffer; bytecount % SM3_BLOCK_SIZE bytes are valid
+ */
+struct sm3_ctx {
+	struct sm3_block_state state;
+	u64 bytecount;
+	u8 buf[SM3_BLOCK_SIZE] __aligned(__alignof__(__be64));
+};
+
+/**
+ * sm3_init() - Initialize an SM3 context for a new message
+ * @ctx: the context to initialize
+ *
+ * If you don't need incremental computation, consider sm3() instead.
+ *
+ * Context: Any context.
+ */
+void sm3_init(struct sm3_ctx *ctx);
+
+/**
+ * sm3_update() - Update an SM3 context with message data
+ * @ctx: the context to update; must have been initialized
+ * @data: the message data
+ * @len: the data length in bytes
+ *
+ * This can be called any number of times.
+ *
+ * Context: Any context.
+ */
+void sm3_update(struct sm3_ctx *ctx, const u8 *data, size_t len);
+
+/**
+ * sm3_final() - Finish computing an SM3 message digest
+ * @ctx: the context to finalize; must have been initialized
+ * @out: (output) the resulting SM3 message digest
+ *
+ * After finishing, this zeroizes @ctx.  So the caller does not need to do it.
+ *
+ * Context: Any context.
+ */
+void sm3_final(struct sm3_ctx *ctx, u8 out[at_least SM3_DIGEST_SIZE]);
+
+/**
+ * sm3() - Compute SM3 message digest in one shot
+ * @data: the message data
+ * @len: the data length in bytes
+ * @out: (output) the resulting SM3 message digest
+ *
+ * Context: Any context.
+ */
+void sm3(const u8 *data, size_t len, u8 out[at_least SM3_DIGEST_SIZE]);
+
+#endif /* _CRYPTO_SM3_H */